The present invention relates generally to washing machines, and more particularly, to a combination dynamic balancer for a wash basket of a vertical axis washing machine.
It is common to spin a wash basket of a washing machine at high speed to extract washing fluid from the laundered articles within the basket. Invariably, the wet articles within the basket are not evenly distributed and create an unbalanced condition during the high speed spinning cycles of the machine. The unbalanced condition creates a rotating wash basket mass that does not correspond to the rotational axis of the wash basket and the washing machine. This generates unwanted stress on the components of the machine, excessive noise, severe vibration of the wash basket, and often movement of the machine. The loads created by the out of balance condition as well as the severe vibration can also create excessive wear and damage to the components of the washing machine.
It is therefore imperative that the wash basket including the wet articles therein be balanced to avoid these unwanted results. However, this is difficult because the out of balance condition varies from load to load and from machine to machine depending on the size of the machine, the quantity and weight of the articles being laundered and the variable positioning of the articles within the basket from load to load. The out of balance condition also varies for each load as the amount of water extracted from the articles within the basket changes during the period of each spin cycle. Therefore, it is imperative that any balancing mechanisms utilized in conjunction with the washing machine to correct these out of balance conditions be dynamic in nature.
One type of commonly used balancing device is known as a liquid balancing ring attached to the top of the basket. A typical liquid balancer ring includes an annular chamber that is partly filled, typically just over half full, with a fluid. This relatively simple balancer ring permits the fluid within the annular chamber to collect unevenly within the ring to offset an unbalanced condition of the wash basket. U.S. Pat. No. 5,345,792 discloses multiple liquid balancing rings.
Another type of balancer is known as a ball balancer and is typically utilized on horizontal axis washing machines. A ball balancer has a hollow annular chamber in a balancing ring wherein a plurality of steel balls are held within the chamber. These balls roll through a viscous fluid also held within the chamber. The annular chamber is completely filled with fluid once the steel balls are placed in the chamber. The rolling balls can distribute unevenly within the chamber to offset an unbalanced condition in the wash basket. The viscous fluid tempers movement of the balls within the chamber. U.S. Pat. Nos. 5,593,281 and 5,802,885 discloses a ball balancing ring.
Another type of balancing device utilized on horizontal axis automatic washing machines is a combination ball and liquid balancer. This type of device includes an annular ring that is divided into two hollow annular chambers that are essentially concentric or stacked upon one another. One of the chambers houses a ball balancer as described above and the other chamber houses a liquid balancer also as described above. This type of device functions wherein the balls can shift to a position opposite the unbalance condition or heavy side of the wash basket for small unbalances. If the balancing balls are completely shifted and the wash basket still spins with some vibration, the liquid balancing portion of the combined device further reduces the unbalance condition by shifting liquid to collect opposite the out of balance condition or heavy side of the wash basket. This combination ball and liquid balancer therefore simply extends the range of unbalance that a normal ball balancing device could handle. The combined liquid and ball balancer described above also provides somewhat of an improvement for wash basket stability during start up and also when a wash basket is spinning at high speeds and is empty. One example of a combination balancer is disclosed in WO99/10583.
The above balancing devices have their limitations. They can only cover limited ranges of out of balance conditions for vertical axis washing machines. Additionally, the ball balancer has typically not been used on vertical axis washing machines.
One object of the present invention is to provide a balancing device for a vertical axis washing machine. Another object of the present invention is to provide a balancing device for automatic washing machines that provides an increased range of unbalance coverage over prior balancing devices. A further object of the present invention is to provide a balancing device that produces such increased range without increasing the cost of the balancing device. A still further object of the present invention is to provide a balancing device for automatic washing machines that has three separate balancing elements or characteristics producing a triple balancing device.
To achieve these and other objects, features and advantages of the present invention, a balancing device in one embodiment is constructed as an annular ring divided into two separate hollow annular chambers. A first chamber has a first fluid held therein that only partly fills the first chamber. The second chamber is disposed adjacent the first chamber and has a plurality of objects held therein that are movable within the second chamber. A second fluid is also held in the second chamber and, in combination with the objects, only partly fills the second chamber.
In one embodiment, the first fluid is water. In another embodiment, the first fluid is salt water. In one embodiment, the first fluid fills about one-half of the first chamber.
In one embodiment, the second chamber is stacked on top of the first chamber and is co-axial therewith. In another embodiment, the first chamber is at least partly defined in a first annular material ring and the second chamber is at least partly defined in a second annular material ring. In one embodiment, the second annular ring is stacked on top of the first annular ring and is attached thereto. In one embodiment, a third annular ring is disposed between the first and second annular ring and separates the first and second chambers.
In one embodiment, the dynamic balancer device includes a third injection molded ring of material defining a race. The race is attached to a second upper injection molded annular ring defining an inverted annular channel wherein the second chamber is defined between the race and the upper ring. A first lower injection molded ring of material that defines an annular channel is attached to the combined race and upper ring and defines the first chamber between the lower ring and the race. In one embodiment, each of these injection molded compartments is adhered to one another by heat welding, sonic welding, spin welding, or hot plate welding.
In one embodiment, the upper ring includes a pair of opposed depending walls and the race includes a pair of opposed edges that are attached to the depending walls of the upper ring. The lower ring includes a pair of upstanding and opposed walls. The lower ring is connected to the combined upper ring and race so that the attachment joints between the race and upper ring are received in the first chamber between the upstanding walls of the lower ring.
In one embodiment, the plurality of objects are each capable of rolling within the second chamber. In one embodiment, the objects are spherical balls. In another embodiment, the balls are steel balls.
In one embodiment, the second fluid has a higher viscosity than the first fluid. In one embodiment, the second fluid is an oil. In one embodiment, the oil is a ten weight oil. In one embodiment, the second fluid and the solid bodies, in combination, fill about one-half of the second chamber.
In another embodiment of the invention, an automatic washer includes an imperforate tub and a perforate wash basket disposed within the tub. The wash basket is rotatable about a generally vertical axis and has an annular top edge defining an opening. A rotary dynamic balancer is associated with the top edge of the wash basket and includes an annular hollow first chamber. A first fluid is held in the first chamber and only partly fills the chamber. An annular hollow second chamber is disposed adjacent to the first chamber and includes a plurality of solid bodies disposed therein. The solid bodies are movable within the second chamber. A second fluid is held within the second chamber and, in combination with the solid bodies, only partly fills the second chamber.